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    <H1 CLASS="title">Function Template <CODE>tee</CODE></H1>
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<DL class="page-index">
  <DT><A href="#description">Description</A></DT>
  <DT><A href="#headers">Headers</A></DT>
  <DT><A href="#reference">Reference</A></DT>
</DL>

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<A NAME="description"></A>
<H2>Description</H2>

<P>
    The class templates <CODE>tee_filter</CODE> and <CODE>tee_device</CODE> provide two ways to split an output sequence so that all data is directed simultaneously to two different locations. A <CODE>tee_filter</CODE> is an <A HREF="../concepts/output_filter.html">OutputFilter</A> which copies all data to a <A HREF="../concepts/sink.html">Sink</A> specified at construction in addition to passing it downstream unmodified.  A <CODE>tee_device</CODE> is a <A HREF="../concepts/sink.html">Sink</A> which copies all data to two Sinks specified at construction.
</P>

<P>
    The overloaded function template <A HREF='#tee'><CODE>tee</CODE></A> is an <A HREF='http://www.boost.org/more/generic_programming.html#object_generator' TARGET='_top'>object generator</A> which given a Sink or a pair of Sinks returns an appropriate specialization of <CODE>tee_filter</CODE> or <CODE>tee_device</CODE>.
</P>

<A NAME="headers"></A>
<H2>Headers</H2>

<DL class="page-index">
  <DT><A CLASS="header" HREF="../../../../boost/iostreams/tee.hpp"><CODE>&lt;boost/iostreams/tee.hpp&gt;</CODE></A></DT>
</DL>

<A NAME="reference"></A>
<H2>Reference</H2>

<A NAME="synopsis"></A>
<H4>Synopsis</H4>

<PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {

<SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_filter_template_params'>Sink</A>&gt;
<SPAN CLASS='keyword'>class</SPAN> <A CLASS='documented' HREF='#tee_filter'>tee_filter</A> {
<SPAN CLASS='keyword'>public:</SPAN>
    <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='keyword'>typename</SPAN> char_type_of&lt;Sink&gt;::type  char_type;
    <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>[implementation-defined]</SPAN>           category;

    <SPAN CLASS='keyword'>explicit</SPAN> <A CLASS='documented' HREF='#tee_filter_ctor'>tee_filter</A>([<SPAN CLASS='keyword'>const</SPAN>] Sink&amp; snk);

    <SPAN CLASS='comment'>// OutputFilter member functions</SPAN>
};

<SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_device_template_params'>Sink1</A>, <SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_device_template_params'>Sink2</A>&gt;
<SPAN CLASS='keyword'>class</SPAN> <A CLASS='documented' HREF='#tee_device'>tee_device</A> {
<SPAN CLASS='keyword'>public:</SPAN>
    <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='keyword'>typename</SPAN> char_type_of&lt;Sink1&gt;::type  char_type;
    <SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>[implementation-defined]</SPAN>            category;

    <A CLASS='documented' HREF='#tee_device_ctor'>tee_device</A>([<SPAN CLASS='keyword'>const</SPAN>] <SPAN CLASS='keyword'>const</SPAN>&amp; sink1, [<SPAN CLASS='keyword'>const</SPAN>] Sink2&amp; sink2);

    <SPAN CLASS='comment'>// Sink member functions</SPAN>
};

<SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_unary_template_params'>Sink</A>&gt;
<A CLASS='documented' HREF='#tee_filter'>tee_filter</A>&lt;Sink&gt; <A CLASS='documented' HREF='#tee_unary'>tee</A>([<SPAN CLASS='keyword'>const</SPAN>] Sink&amp; snk);

<SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_binary_template_params'>Sink1</A>, <SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='#tee_binary_template_params'>Sink2</A>&gt;
<A CLASS='documented' HREF='#tee_device'>tee_device</A>&lt;Sink1, Sink2&gt; <A CLASS='documented' HREF='#tee_binary'>tee</A>([<SPAN CLASS='keyword'>const</SPAN>] Sink1&amp; sink1, [<SPAN CLASS='keyword'>const</SPAN>] Sink2&amp; sink2);


} } // End namespace boost::io</PRE>

<A NAME="tee_filter"></A>
<H2>Class Template <CODE>tee_filter</CODE></H2>

<H4>Description</H4>

<P>An <A HREF='../concepts/output_filter.html'>OutputFilter</A> which copies all data which passes through it to a <A HREF='../concepts/sink.html'>Sink</A> specified at construction. A <CODE>tee_filter</CODE> is <A HREF='../concepts/closable.html'>Closable</A>, <A HREF='../concepts/flushable.html'>Flushable</A>, <A HREF='../concepts/localizable.html'>Localizable</A> and <A HREF='../concepts/optimally_buffered.html'>OptimallyBuffered</A>.</P> 

<A NAME="tee_filter_template_params"></A>
<H4>Template parameters</H4>

<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
    <TR>
        <TD VALIGN="top"><I>Sink</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A></TD>
    </TR>
</TABLE>

<A NAME="tee_filter_ctor"></A>
<H4><CODE>tee_filter::tee_filter</CODE></H4>

<PRE CLASS="broken_ie"><SPAN CLASS='keyword'>explicit</SPAN> tee_filter([<SPAN CLASS='keyword'>const</SPAN>] Sink&amp; sink);</PRE>

<P>
    Constructs an instance of <CODE>tee_filter</CODE> based on the given Sink. The function parameter is a non-<CODE>const</CODE> reference if <CODE>Sink</CODE> is a stream or stream buffer type, and a <CODE>const</CODE> reference otherwise.
</P>

<A NAME="tee_device"></A>
<H2>Class Template <CODE>tee_device</CODE></H2>

<H4>Description</H4>

<P>A <A HREF='../concepts/sink.html'>Sink</A> which copies all data to each of two Sinks specified at construction. A <CODE>tee_device</CODE> is <A HREF='../concepts/closable.html'>Closable</A>, <A HREF='../concepts/flushable.html'>Flushable</A>, <A HREF='../concepts/localizable.html'>Localizable</A> and <A HREF='../concepts/optimally_buffered.html'>OptimallyBuffered</A>.</P> 

<A NAME="tee_device_template_params"></A>
<H4>Template parameters</H4>

<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
    <TR>
        <TD VALIGN="top"><I>Sink1</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A></TD>
    </TR>
    <TR>
        <TD VALIGN="top"><I>Sink2</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A> with the same <A HREF='../guide/traits.html#char_type'>character type</A> as <I>Sink1</I></TD>
    </TR>
</TABLE>

<A NAME="tee_device_ctor"></A>
<H4><CODE>tee_device::tee_device</CODE></H4>

<PRE CLASS="broken_ie">tee_device([<SPAN CLASS='keyword'>const</SPAN>] <SPAN CLASS='keyword'>const</SPAN>&amp; sink1, [<SPAN CLASS='keyword'>const</SPAN>] Sink2&amp; sink2);</PRE>

<P>
    Constructs an instance of <CODE>tee_device</CODE> based on the given pair of Sinks. Each function parameter is a non-<CODE>const</CODE> reference if the corresponding template argument is a stream or stream buffer type, and a <CODE>const</CODE> reference otherwise.
</P>

<A NAME="tee"></A>
<A NAME="tee_unary"></A>
<H2>Function Template <CODE>tee</CODE></H2>

<PRE CLASS="broken_ie"><SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> Sink&gt;
tee_filter&lt;Sink&gt; tee([<SPAN CLASS='keyword'>const</SPAN>] Sink&amp; snk);</PRE>

<A NAME="tee_unary_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
    <TR>
        <TD VALIGN="top"><I>Sink</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A></TD>
    </TR>
</TABLE>

<P>
    Constructs an instance of an appropriate specialization of <CODE>tee_filter</CODE> based on the given Sink. The function parameter is a non-<CODE>const</CODE> reference if <CODE>Sink</CODE> is a stream or stream buffer type, and a <CODE>const</CODE> reference otherwise.
</P>

<A NAME="tee_binary"></A>
<PRE CLASS="broken_ie"><SPAN CLASS='keyword'>template</SPAN>&lt;<SPAN CLASS='keyword'>typename</SPAN> Sink1, <SPAN CLASS='keyword'>typename</SPAN> Sink2&gt;
tee_device&lt;Sink1, Sink2&gt; tee([<SPAN CLASS='keyword'>const</SPAN>] Sink1&amp; sink1, [<SPAN CLASS='keyword'>const</SPAN>] Sink2&amp; sink2);</PRE>

<A NAME="tee_binary_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
    <TR>
        <TD VALIGN="top"><I>Sink1</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A></TD>
    </TR>
    <TR>
        <TD VALIGN="top"><I>Sink2</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A <A HREF='../concepts/blocking.html'>Blocking</A> <A HREF='../concepts/sink.html'>Sink</A></TD>
    </TR>
</TABLE>

<P>
    Constructs an instance of an appropriate specialization of <CODE>tee_device</CODE> based on the given pair of Sinks. Each function parameter is a non-<CODE>const</CODE> reference if the corresponding template argument is a stream or stream buffer type, and a <CODE>const</CODE> reference otherwise.
</P>

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    Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <A HREF="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>)
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